Throughthe specific circumstances of large experimental equipment to carry out in-depth study of measurability, making large experimental facilities and equipment related to the relevant managers, designers, testers, users and maintenance personnel canintegrate measurability idea into their own work. By means of measurement, the parameters of the large experimental equipment, especially the output parameters of the system level can be traced back to the approved national measurement standards, and ultimately to achieve effective control of the technical state of the system.